Response of forage quality of the dominant species to short-term grazing in the alpine meadow at Qinghai-Tibetan Plateau

This study was aimed to understand the effect of grazing intensity on forage quality of the dominant species, Polygonum viviparum and Kobresia capillifolia, of the alpine meadow in the northeastern edge region of Qinghai-Tibetan Plateau. The changes in forage total nitrogen, acid detergent fiber, neutral detergent fiber, total digestible nutrients and relative feeding value were measured under light (0.75 cattle units·ha-1), moderate (1.00 cattle units·ha-1) and heavy (1.25 cattle units·ha-1) grazing intensities. At the end of grazing, plant height of the two dominant species under moderate grazing intensity was significantly higher than those under other intensities (P0.05). During the whole grazing, forage total nitrogen under moderate grazing was higher than those under other intensities, and it was significantly higher at the end of grazing than that under heavy grazing intensity for P.viviparum (P0.05). There was no significant difference in the contents of acid and neutral detergent fiber among different grazing intensities at the end of grazing. Nutritional value index showed a rising trend or kept stable under moderate grazing. Conclusively, the moderate grazing intensity was helpful to the dominant species, P.viviparum and K.capillifolia, in the alpine meadow at the northeastern edge of Qinghai-Tibetan Plateau to remain higher and stable forage quality.